Evaporator for refrigerators



FURY-31, 1934. c; w MASON EVAPORATOR FQR REFRIGERATORS Filed April 11. 1929 G. WMAS 0N INVENTOR a m M 3 1 6 j a Q m] C fla a a Jam 2625M;

ATTORNEY Patented Jul 31, 1934 PATENT OFFICE 1,968,048 EVAPORA'I'OR roa nnrmcmwrons George W. Mason, Detroit, Mich, assignor to- Kelvinator Corporation, Detroit, Mich, a corporation of Michigan Application April 11, 1929, Serial No. 354,348

14 Claims.

This invention relates to apparatus for effecting artificial refrigeration and it has particular relation to an apparatus of the above designated character to be employed in refrigeration cabinets especially applicable for domestic use.

An object of the invention is to provide an emcient apparatus for freezing water or other substances in trays adapted to be disposed in thermal contact with a heat absorbing unit.

Another object of the invention is to provide a refrigerant evaporating unit in which heat will be absorbed both from the top and bottom portions of a freezing tray.

Prior to the invention, it has been the practice to provide refrigerant evaporating units designed especially for the purpose of maintaining a space, in which such evaporating unit was located, at a predetermined average temperature. While such evaporating units embodied regions inwhich water or other food substances might be frozen, it was not possible to accomplish this purpose in a minimum amount of time without totally changing the operational characteristics of the apparatus. When this was done, obviously a great amount of energy was totally wasted by cooling the space surrounding the evaporating unit to a much lower temperature than was required under normal conditions of operation.

This invention is characterized by a structure in which a tray, for containing warm substances to be frozen, is disposed in such relation to a device for controlling the operation of the apparatus. that heat fromv the tray will effect the operation of the aforesaid device within a very short time after such tray is inserted in the evaporating unit. In addition means is'provided for exchanging heat between the tray and the evaporating unit at an average rate almost as great as the capacity of the refrigeration apparatus thus preventing a reduction in the temperature of the evaporating unit to sucha degree that its operation will be discontinued by the controlling device before the substance, contained in a freezing tray, is frozen. In order to increase the normal rate of heat exchange be-' U tween the contacting surfaces of the tray and evaporating'unit, the invention provides means for exerting a pressure upon the freezing tray in order to prevent its being supported by a relatively small number of widely distributed points. The pressure applying means contacts thermally with an upper portion of the freezing tray and thus forms the additional function of conducting heat from the upper surface of the tray to the evaporating unit.

For a better understanding of the invention, reference may now be had to the accompanying drawing, forming a part of this specification, in which:

Figure 1 is a fragmentary cross-sectional view of a refrigerator cabinet in which an evaporating unit, embodying one form which the invention may assume, is located;

Figure 2 is a longitudinal cross-sectional view of the evaporating unit illustrated byFigure 1;

Figure 3 is a diagrammatical view illustrating a condensing unit which may be incorporated in a refrigerating apparatus embodying the invention.

A refrigerant evaporating unit 10, employed in practising the invention, is secured rigidly in any suitable manner (not shown) in an upper portion of a refrigerator cabinet 11.

The evaporating unit comprises a brine tank 12 having a filler cap 13 through which the tank is adapted to be filled. A high pressure liquid refrigerant line 14, communicating with a condenser 16 of a refrigerant'condensing unit 17, is' connected at its opposite end to a refrigerant expansion valve 18, secured by bolts (not shown) to a boss 19 disposed in an opening in an upper corner portion of the brine tank 12. Refrigerant liquid is expanded by the valve 18 into a section 21 of an expansion conduit 22 which is distributed throughout the interior of the tank in any. manner suitable for cooling the brine solution therein.

A second section 23 of the expansion conduit 22 is disposed externally of the tank 12 on the upper surface of the bottom of a horizontally disposed sleeve 24 projecting internally of the tank. The expansion conduit section 23 is secured rigidly in good thermal contact with the bottom of the sleeve 24 by soldering as indicated at 26 for transferring its-capacity for freezing 1 ice within the interior of the sleeve and to the brine in tank 12 for cooling the interior of a refrigerator.

A thermostat 2'7 is provided with an expansible fluid containing bulb 28 which is secured by a metallic clip 29 to an end portion of the expansion conduit section 23 projecting beyond one end of the sleeve 24. This conduit merges adjacent the thermostat 27 into a suction line 31 which communicates with the low side of a refrigerant compressor 32; The theremostat 27 is provided with conductors 33 by means of which it is connected in the positive side of a power line 34 for supplying electrical energy to a motor 36. The compressor 32 is adapted to be driven by a motor 36 through a belt power transmission device 37. The thermostat 27 is so constructed that it will open the circuit through the motor 36 when it is affected by a predetermined minimum temperature and, likewise, will close such circuit when affected by a predetermined maximum temperature.

A freezing tray 38, adapted to be inserted within the sleeve 24, is provided with a bottom portion 39 contacting thermally with the upper surface of the section 23 of the expansion conduit 22, throughout substantially the entire length of the latter.

A grid 41 disposed within the freezing tray 38 divides the latter into a plurality of separate compartments for containing the substances to be frozen. A resilient plate 42, secured to the top of the sleeve 24, as indicated at 43, is provided with a parallel pair of downwardly projecting flanges 44, for engaging the opposite longitudinal edge portions 46 of the freezing tray 38, and a downwardly curved intermediate portion 47, for engaging the upper end portions 48 and substantially the entire upper surface of the grid 41. The formation of the resilient plate 42 and its disposition within the sleeve 24 is such that it is compressed materially by the freezing tray 38 when it is inserted within the sleeve 24. As a result of such compression of the plate 42, it is apparent that the freezing tray 38 will be urged downwardly against the expansion conduit section 23 thus materially increasing the number of points of metallic contact therewith.

It is to be understood that is is very diflicult to construct freezing trays of a uniform character. Out of a large number of such trays all constructed in substantially the same manner, it will be found that many will have either concave or convex bottom portions and that very few will be exactly identical. Consequently, those not corresponding to a heat absorbing surface, on which the trays are adapted to be supported, will have far less surface contact therewith than one having a bottom portion exactly similar to the supporting surface. Since the resilient plate 42 exerts a pressure both on the tray 38 and the grid 41, the bottom of the tray will be urged into thermal contact with the expansion conduit section 23 throughout substantially its entire length notwithstanding the fact that its bottom surface may be slighly imperfect in formation.

It is to be understood that the application of the invention is not limited to any particular type of refrigerating apparatus but may be embodied in any structure where its cardinal principles can be utilized. While brine as a heat retaining medium is considered preferable, it is possible to employ cast metal, earthenware or other suitable substances. If preferred, however, such heat retaining mediums may be eliminated entirely. Likewise, the freezing tray is not required to be disposed in direct thermal contact with an expansion coil but some intermediate heat conducting material may be employed between them if desired.

Although the specification disclosesonly the preferred form of the invention, and describes in detail but a single application thereof, it will be apparent to those skilled in the art that the invention is not so limited, but that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What I claim is:

1. A refrigerant evaporating unit comprising a heat retaining medium having a horizontally disposed portion, refrigerant evaporating means disposed internally of said heat retaining medium, and refrigerant evaporating means disposed externally of the heat retaining medium in thermal contact with the upper surface of the aforesaid horizontal portion thereof.

2. A refrigerant evaporating unit comprising a heat retaining medium having a horizontally disposed planular surface portion, an evaporating conduit havinga continuous planular section disposed in thermal contact with the aforesaid planular surface portion of the heat retaining medium, a freezing tray adapted to be supported upon the upper surface of the evaporating conduit, and a thermostat thermally connected to the conduit for actuating the refrigerant expansion unit in response to the temperature of the aforesaid freezing tray.

3. A refrigerant evaporating unit comprising a heat retaining medium having an aperture formed therein, a continuous sinuously wound refrigerant expansion conduit supported therein in thermal contact with a lower portion thereof, a freezing tray adapted to be supported by the aforesaid conduit, and a thermostat connected directly to the conduit for actuating the evaporating unit in response to the temperature of the freezing tray.

4. A refrigerant evaporating unit comprising a heat retaining medium having an aperture formed therein, a refrigerant evaporating conduit having a plurality of sections disposed in a single plane and adapted to be supported in the bottom of the aforesaid aperture in thermal contact with the heat retaining medium, and a freezing tray disposed on the upper surface of the aforesaid conduit.

5. A refrigerant evaporating-unit comprising a heat retaining medium having a refrigerant expansion coil disposed internally thereof, and a refrigerant expansion coil disposed externally of the medium in metallic heat conductive relationship thereto.

6. A refrigerant evaporating unit comprising means for evaporating a refrigerant fluid, a freezing tray disposed in thermal contact with the means, and means for pressing the freezing tray downwardly against the first mentioned means to provide efficient thermal contact therewith.

7. A refrigerant evaporating unit comprising means for evaporating a refrigerant fluid, a freezing tray adapted to be supported by the aforesaid means, and a resilient member adapted to be pressed against the upper surface of the freezing tray for urging the latter into intimate thermal contact with the refrigerant evaporating means.

8. A refrigerant evaporating unit comprising means for evaporating a refrigerant fluid, a resilient metallic member conductively associated therewith, and a freezing tray for insertion beneath the resilient member in intimate contact therewith.

9. A refrigerant evaporating unit comprising a brine tank having an aperture formed therein, a refrigerant fluid evaporating coil disposed internally of the brine tank, a second refrigerant fluid evaporating conduit communicating with the first mentioned conduit, and disposed in the bottom of the aforesaid aperture in thermal contact with the brine tank, a freezing tray adapted to be supported by the last mentioned conduit, and a resilient member secured in the top of the aperture for pressing the freezing tray downwardly against the last mentioned fluid evaporating conduit.

10. A refrigerant evaporating unit comprising means for evaporating refrigerant fluid, a sleeve for supporting a freezing tray, a freezing tray having its bottom wall supported within said sleeve, and means within said sleeve in direct contact with the upper extremity of the tray for conducting heat to the refrigerant evaporating means.

11. A refrigerant evaporating unit comprising a refrigerant expansion conduit having a freezing tray supported thereon, said conduit having a portion extending above said tray,

and a resilient member engaging an upper portion of the freezing tray and in thermal contact with the portion of said conduit extending above said tray for conducting heat thereto from the tray.

12. A refrigerant evaporating unit comprising means for evaporating a refrigerant fluid, a freezing tray disposed adjacent thereto, a grid within the latter for dividing it into a. plurality of compartments, and a resilient metallic member in thermal contact with the upper surface of the grid and the evaporating means for conducting heat from the grid to the aforesaid fluid evaporating means.

13. A refrigerant evaporating unit comprising means containing a volatile refrigerant, a freezing tray disposed in thermal contact with the means, and means for pressing the freezing tray throughout its length against and in thermal contact with said first mentioned means and into the same plane as the plane of the said mentioned means.

14. A refrigerant evaporating unit comprising means containing a volatile refrigerant, a freezing tray disposed in intimate thermal contact with said means, and a resilient heat conducting member coextensive with the length of the tray and in contact therewith for pressing said tray in thermal contact with said first mentioned means.

GEORGE W. MASON. 

